Modeling void development in irradiated metals in the phase-field framework

Abstract Phase-field modeling of void ensemble development under simultaneous generation of vacancies and interstitials is considered. Void nucleation is treated as precipitation in a metastable point-defect solution via classical nucleation theory, driven by stochastic fluctuations arising both from correlated point-defect production in collision cascades and random diffusion jumps. A statistical approach derives a formulation in which driving forces for the evolution of the void ensemble can be modeled through a Cahn–Hilliard-type functional. The functional is not equivalent to the actual thermodynamic potential when vacancies and SIAs are simultaneously present, but the model is thermodynamically consistent and satisfies the fluctuation–dissipation theorem in the thermodynamic limit. The model is tested by comparing with the evolutionary characteristics of the void ensemble in the sharp interface model solved via a master-equation approach.